Partial oxidation and combined reforming of methane on Ce-promoted catalysts

Abstract

Pt/ZrO 2 and Pt/Ce 0.14Zr 0.86O 2 catalysts containing 0.5 and 1.5 wt.% Pt were studied in order to evaluate the effect of the support reducibility and metal dispersion on the catalyst stability for the partial oxidation and the combined partial oxidation and CO 2 reforming of methane. The Pt/Ce 0.14Zr 0.86O 2 catalysts proved to be more active, stable and selective than Pt/ZrO 2 catalysts during the partial oxidation reaction. No increase in deactivation was observed when the CH 4:O 2 feed ratio was increased from 2:1 to 4:1. In addition, no water formation was observed at the high CH 4:O 2 ratios. The activity of the catalyst is dependent upon both the dispersion and the ability of the catalyst to resist carbon deposition. The addition of CO 2 resulted in a decrease in the methane conversion and a decrease in the H 2/CO ratio for the Ce 0.14Zr 0.86O 2 and ZrO 2 supported catalysts. Small increases in the temperature of the bed have been recorded during the partial oxidation reaction. However, within a few minutes the temperature stabilizes below the furnace temperature providing indirect evidence for the combined combustion and reforming mechanisms previously proposed. The 1.5 wt.% Pt/CeZrO 2 catalyst shows promise for the autothermal reforming reaction based on the stability during transient operation.